Compilare: user.cpp: In function ‘int main()’: user.cpp:22:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(st.size()+n-i<m) st.push(s); ^ user.cpp:25:68: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(!st.empty() && st.top()<s && st.size()+n-i>=m) ^ user.cpp:27:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(st.size()<m) st.push(s); ^ user.cpp:11:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("trompeta.in","r",stdin); ^ user.cpp:12:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("trompeta.out","w",stdout); ^ user.cpp:15:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n",&n,&m); ^ user.cpp:18:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c",&s); ^